Conventionally, there has been known a power supply controlling apparatus that stores electric power information (e.g. a current value and a voltage value) concerning electric power supplied to another apparatus as a history into a nonvolatile storage.
For example, a document 1 (Japanese Laid-Open Patent Application No. 2008-167544) discloses an electric power controlling system that reads out from a nonvolatile memory power consumption that increases after a printer starts, and controls the start-up of the printer by comparing the power consumption with usable electric energy.
For example, a document 2 (Japanese Laid-Open Patent Application No. 2005-301476) discloses a feeding control system that stores a history of voltage data in a volatile memory. When the power dispatching control system detects an interrupt signal, the power dispatching control system transfers the voltage data stored in the volatile memory to a nonvolatile storage, and analyzes a reason of abnormality.
Incidentally, there is a power supply controlling apparatus that separately includes a power supply of the power supply controlling apparatus and a power supply supplying electric power to another apparatus, and does not stop supplying the electric power to the another apparatus even when the power supply of the power supply controlling apparatus is turned off. Also, as a method of leaving the history of electric power information concerning the electric power supplied to another device into the nonvolatile storage, there is a method of writing the electric power information in a volatile storage at constant intervals, and then writing the electric power information written in the volatile storage in the nonvolatile storage in desired timing.
However, in the above-mentioned construction, when the power supply of the power supply controlling apparatus is turned off after the electric power information is written in the nonvolatile storage, and then the power supply of the power supply controlling apparatus is turned on again, electric power information from time when the electric power information is written in the nonvolatile storage to time when the power supply of the power supply controlling apparatus is turned on again is not stored into the nonvolatile storage, and hence the electric power information of the time period is lost.